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2j0p
From Proteopedia
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==Overview== | ==Overview== | ||
| - | Bacteria rely on their environment and/or host to acquire iron and have, evolved specialized systems to sequester and transport heme. The heme, uptake system HemRSTUV is common to proteobacteria, and a major challenge, is to understand the molecular mechanism of heme binding and transfer, between the protein molecules that underlie this heme transport relay, process. In the Gram-negative pathogen Yersinia enterocolitica, the, HemRSTUV system culminates with the cytoplasmic recipient HemS, which, stores and delivers heme for cellular needs. HemS belongs to a family of, proteins essential and unique to proteobacteria. Here we report on the, binding mechanism of HemS based on structural data from its apo- and, ligand-loaded forms. This heme carrier protein associates with its cargo, through ... | + | Bacteria rely on their environment and/or host to acquire iron and have, evolved specialized systems to sequester and transport heme. The heme, uptake system HemRSTUV is common to proteobacteria, and a major challenge, is to understand the molecular mechanism of heme binding and transfer, between the protein molecules that underlie this heme transport relay, process. In the Gram-negative pathogen Yersinia enterocolitica, the, HemRSTUV system culminates with the cytoplasmic recipient HemS, which, stores and delivers heme for cellular needs. HemS belongs to a family of, proteins essential and unique to proteobacteria. Here we report on the, binding mechanism of HemS based on structural data from its apo- and, ligand-loaded forms. This heme carrier protein associates with its cargo, through a novel, partly preformed binding pocket, formed between a large, beta-sheet dome and a three-helix subdomain. In addition to a histidine, interacting with the iron, the complex is stabilized by a distal, non-coordinating arginine that packs along the porphyrin plane and, extensive electrostatic contacts that firmly anchor the heme propionate, groups within the protein. Comparison of apo- and ligand-bound HemS, crystal structures reveals striking conformational changes that underlie a, "heme-induced fit" binding mechanism. Local shifts in amino acid positions, combine with global, rigid body-like domain movements, and together, these, bring about a switch from an open, apo-form to a closed, bound state. This, is the first report in which both liganded and unliganded forms of a heme, transport protein are described, thus providing penetrating insights into, its mechanism of heme binding and release. |
==About this Structure== | ==About this Structure== | ||
| - | 2J0P is a | + | 2J0P is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Yersinia_enterocolitica Yersinia enterocolitica] with HEM, 12P, MLI and PEG as [http://en.wikipedia.org/wiki/ligands ligands]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2J0P OCA]. |
==Reference== | ==Reference== | ||
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[[Category: transport]] | [[Category: transport]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 13:36:15 2007'' |
Revision as of 11:30, 5 November 2007
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STRUCTURE OF THE HAEM-CHAPERONE PROTEOBACTERIA-PROTEIN HEMS
Overview
Bacteria rely on their environment and/or host to acquire iron and have, evolved specialized systems to sequester and transport heme. The heme, uptake system HemRSTUV is common to proteobacteria, and a major challenge, is to understand the molecular mechanism of heme binding and transfer, between the protein molecules that underlie this heme transport relay, process. In the Gram-negative pathogen Yersinia enterocolitica, the, HemRSTUV system culminates with the cytoplasmic recipient HemS, which, stores and delivers heme for cellular needs. HemS belongs to a family of, proteins essential and unique to proteobacteria. Here we report on the, binding mechanism of HemS based on structural data from its apo- and, ligand-loaded forms. This heme carrier protein associates with its cargo, through a novel, partly preformed binding pocket, formed between a large, beta-sheet dome and a three-helix subdomain. In addition to a histidine, interacting with the iron, the complex is stabilized by a distal, non-coordinating arginine that packs along the porphyrin plane and, extensive electrostatic contacts that firmly anchor the heme propionate, groups within the protein. Comparison of apo- and ligand-bound HemS, crystal structures reveals striking conformational changes that underlie a, "heme-induced fit" binding mechanism. Local shifts in amino acid positions, combine with global, rigid body-like domain movements, and together, these, bring about a switch from an open, apo-form to a closed, bound state. This, is the first report in which both liganded and unliganded forms of a heme, transport protein are described, thus providing penetrating insights into, its mechanism of heme binding and release.
About this Structure
2J0P is a Single protein structure of sequence from Yersinia enterocolitica with HEM, 12P, MLI and PEG as ligands. Structure known Active Site: AC1. Full crystallographic information is available from OCA.
Reference
An induced fit conformational change underlies the binding mechanism of the heme transport proteobacteria-protein HemS., Schneider S, Sharp KH, Barker PD, Paoli M, J Biol Chem. 2006 Oct 27;281(43):32606-10. Epub 2006 Aug 30. PMID:16943192
Page seeded by OCA on Mon Nov 5 13:36:15 2007
Categories: Single protein | Yersinia enterocolitica | Barker, P.D. | Paoli, M. | Schneider, S. | Sharp, K. | 12P | HEM | MLI | PEG | Conformational changes | Haem | Haem-binding protein | Ion transport | Iron | Iron transport | Proteobacteria | Transport
